Diverse Origins of Xenoliths from Seamounts at the Continental Margin, Offshore Central California

A diverse assemblage of small mafic and ultramafic xenoliths occurs in alkalic lava from Davidson and Pioneer seamounts located at the continental margin of central California. Based on mineral compositions and textures, they form three groups: (1) mantle xenoliths of lherzolite, pyroxenite, and dunite with olivine of >Fo90; (2) ocean crust xenoliths of dunite with olivine